Since both the Avengers and Ghost Rider 2 have been released, I (being the nerd that I am) has to go on a rant on why Ghost Rider should be in the Avengers. If you don't know Ghost Rider is a anti-hero that fights evil in the form of an insane flaming demon with a awesome motorcycle and a chain that, like himself, are on fire. The Avengers are a group of other primary Marvel characters consisting of mainly Captain America, Iron Man, Thor and Hulk. My reasoning for why Ghost Rider should be in the Avengers is that Hulk, who like Ghost Rider, is a hero who turns into something of a monster and goes on a rampage. The primary reason Ghost Rider isn't the Avengers is because he has a vengeance type thing going on, and that prevents him from being in the Avengers. Hulk is in the Avengers and also has a vengance type thing going on. Why isn't Ghost Rider in the Avengers even when a great amount of his fan base would probably like him to in the Avengers? I have no idea. You could say that the Ghost Rider has a much bigger mission in which he has to defeat the devil, but there's other villians for him to defeat in order to keep him in the Marvel Universe.
Sorry for the late blog....